The present application is based on Japanese Patent Applications No. 2001-81179 and No. 2000-366906, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an ink jet recording apparatus that is provided with a wiping means (cleaner) for wiping off ink adhered to the nozzle forming surface of a recording head.
2. Description of the Related Art
With an ink jet recording apparatus, its printing noise is comparatively small, and small dots can be formed at a high density. Therefore, presently, the ink jet recording apparatus has been widely used for printing including color printing.
Such an ink jet recording apparatus is provided with an ink jet recording head that receives ink from an ink cartridge and a paper feeding means that relatively move recording paper with respect to the recording head.
Recording is carried out by discharging ink drops onto the recording paper while moving the recording head in response to printing signals and forming dots. In this case, a recording head that is capable of discharging ink of, for example, black, yellow, cyan and magenta, is mounted on the carriage, and full-color printing is enabled by varying the ratio of discharge of respective ink.
Thus, in the ink jet recording apparatus, the following problems exist since printing is carried out by discharging ink from nozzles onto recording paper as ink drops. That is, the ink viscosity is increased, resulting from evaporation of an ink solvent through the nozzle openings, ink is solidified on the nozzle forming surface, the nozzle openings are stopped up due to adhesion of dust therein, and bubbles are let in and mixed in the recording head, whereby the printing becomes inferior.
Therefore, the ink jet recording apparatus is provided with a capping means for sealing the nozzle forming surface of the recording head when printing is not executed, a suction pump for sucking ink in and discharging the same into the capping means, and a wiping means (cleaner) for cleaning the nozzle-formed plate of the recording head after ink is sucked in and discharged into the capping means by the suction pump.
In order to prevent the nozzle openings from being clogged and to prevent bubbles from entering the recording head, the nozzle forming surface of the recording head is wiped off (cleaned) by the cleaner after ink is forcibly sucked in and discharged into the capping means by the suction pump.
A process to solve such clogging of the recording head, or a forced discharge process of ink where bubbles remain in the recording head is called a xe2x80x9ccleaning operationxe2x80x9d. The cleaning operation is carried out where printing is re-started after a long-term delay of the recording apparatus and where a user recognizes an inferiority in the printing quality such as a blurring in printing and operates the cleaning switch.
FIG. 24 shows an example of the cleaning member (a part of the cleaner) of related art. In the same drawing, the cleaning member shown by reference number 100 is composed of a rectangular piece made of a resilient material such as rubber, and is attached so as to be erect on the upper part of a sliding member (holder) 101.
In the case of wiping off the nozzle forming surface of the recording head by the cleaning member 100, the sliding member 101 advances in the horizontal direction, and in line with this action, the cleaning member 100 is caused to advance on the movement path of the recording head.
However, in the above-described ink jet recording apparatus, as shown in FIG. 25, the cleaning member 100 is resiliently deformed while being brought into contact with the nozzle forming surface of the recording head 102, in line with the movement of the recording head 102 in the direction shown by the arrow xe2x80x9cAxe2x80x9d. Further, the tip end part of the cleaning member 100 is slidably brought into contact with the nozzle forming surface of the recording head 102 while the tip end part thereof is resiliently deformed by the movement of the recording head 102 in the direction shown by the arrow xe2x80x9cAxe2x80x9d, wherein the surface of the nozzle forming surface is wiped off. Thereby, ink adhered to the nozzle forming surface of the recording head 102 is removed, and it is possible to prevent such a hindrance such as ink uncontrollably dropping from the recording head 102 onto recording paper, etc. during printing.
By further movement of the recording head 102 in the direction shown by the arrow xe2x80x9cAxe2x80x9d, the recording head 102 passes the disposed position of the cleaning member 100. In this case, immediately after (or at the moment when) the recording head 102 has passed through the disposed position of the cleaning member 100, as shown in FIG. 25, the cleaning member 100 is returned in the direction shown by the arrow xe2x80x9cCxe2x80x9d by a resilient reset force (self-restoration force), and is reset to its initial state.
Therefore, at the moment when the cleaning member 100 resiliently returned, ink wiped off from the nozzle forming surface was splashed into the inner mechanism of the recording apparatus, particularly, the driving mechanism of the capping means positioned in the vicinity of the cleaner.
As a result, such a problem occurs, wherein ink is adhered to the driving mechanism (elevation mechanism) of the capping means, and smooth movement of the corresponding driving mechanism is hindered by solidification of the ink, resulting in a decrease of reliability with respect to the operation of the capping means.
In the related art ink jet recording apparatus, since a movement force (advancing and retreating movement) of the cleaner is provided from the drive shaft via a friction clutch (clutch plate and cleaner cam), such a problem arises, wherein smooth movement of the cleaner is not ensured with respect to the advancing and retreating movement, and reliability is lowered in the cleaner movement.
Further, if a pigment-based ink having high ink density is adhered to and is solidified on the friction surface of the friction clutch, it becomes difficult to remove ink, wherein load with respect to the friction clutch becomes uneven due to the amount of solidified ink on the friction surface, and such an inconvenience arises, wherein printing disorders may occur in the case where the drive means of the cleaner (friction clutch) is based on a paper feeding motor.
In addition thereto, since the friction clutch is constructed so as to be driven by drive of the above-described ink suction pump, the pump load is increased when driving the pump, and such an inconvenience arises, wherein durability of the pump is lowered.
The present invention was developed in view of the aforementioned problems, and it is therefore an object of the invention to provide an ink jet recording apparatus that increases the reliability of a capping means and a cleaner with respect to the movement thereof and durability of the pump where the drive shaft of the cleaner is a pump shaft of an ink suction pump, and simultaneously, can prevent printing disorder from occurring where the drive source of the cleaner is based on a paper feeding motor.
An ink jet recording apparatus according to the invention, which has been developed to achieve the aforementioned object is an ink jet recording apparatus that includes a reciprocating carriage; an ink jet recording head, which is mounted on the carriage and discharges ink drops from a nozzle forming surface, corresponding to printing data; and a cleaner, which is disposed in the vicinity of a movement path of the recording head so as to advance and retreat, and has a cleaning member to wipe off the nozzle forming surface; wherein a driving mechanism of the cleaner includes: a drive shaft, having a sun gear, which is rotatably disposed on a fixing base; a gear holding lever that is pivotally and rotatably supported between two rotation stop positions on the drive shaft and rotatably holds a planet gear engaging with the sun gear; and a cleaner drive lever, which is juxtaposed to the gear holding lever, rotatably and pivotally supported at the drive shaft, and has inner teeth engageable with the planet gear; and wherein the cleaner drive lever among these rotates by engagement of the inner teeth with the planet gear due to rotations of the sun gear in a rotation stop state of the gear holding lever, and applies a driving force to the cleaner.
Since the ink jet recording apparatus is thus constructed, the gear holding lever turns counterclockwise if the sun gear (drive shaft) is turned normally (that is, counterclockwise) when setting the cleaner. If the sun gear further rotates counterclockwise, the gear holding lever is further turned counterclockwise, and is locked at a rotation stop position at one side. If the sun gear still further turns counterclockwise in this state, the planet gear is turned clockwise in engagement with the inner teeth to cause the cleaner drive lever to turn clockwise, whereby the cleaner advances in the movement path of the recording head, and the nozzle forming surface of the recording head can be wiped off.
If the sun gear turns counterclockwise after the cleaner advances in the movement path of the recording head, the planet gear is placed at a position apart from the inner teeth, and the planet gear is disengaged from the inner teeth, wherein the cleaner drive lever does not turn.
On the other hand, if the sun gear (drive shaft) is reversed (clockwise) when resetting the cleaner, the gear holding lever turns clockwise. As the sun gear is further turned clockwise, the gear holding lever is further turned clockwise, and is locked at the other rotation stop position. In this state, if the sun gear is still further turned clockwise, the planet gear is turned counterclockwise in engagement with the inner teeth to cause the cleaner drive lever to be turned counterclockwise, whereby the cleaner is retreated from the movement path of the recording head.
If the sun gear is turned clockwise after the cleaner is retreated from the movement path of the recording head, the planet gear is placed at a position apart from the inner teeth, and the planet gear is disengaged from the inner teeth, wherein the cleaner drive lever does not turn.
Therefore, since connection and disconnection of a driving force from the drive shaft with respect to the cleaner are carried out by engagement and disengagement between the planet gear and the inner teeth, the engagement between the planet gear and the inner teeth is released immediately before the recording head passes through the advancing position of the cleaner in the movement path, thereby terminating the cleaning operation, wherein it is possible to prevent ink from being adhering to the driving mechanism of the capping means due to splashing thereof.
Therefore, since smooth movement of the driving mechanism of the capping means is not hindered, the reliability of the capping means can be improved with respect to the movement thereof.
In addition, since a driving force is transmitted from the drive shaft to the cleaner by engagement of the planet gear with the inner teeth, it is possible to securely obtain smooth movement of the cleaner, wherein the reliability with respect to the cleaner movement can be increased, and it is possible to prevent printing disorders from occurring.
Further, if the engagement of the planet gear with the inner teeth is released, it is possible to relieve the pump load where the drive shaft for causing the cleaner to advance and retreat is commonly used as the pump shaft of the ink suction pump, and the durability of the pump can be improved.
In this case, it is preferable that stoppers are provided on the above-described fixing base, corresponding to the above-described two rotation stop positions, and stopper engaging portions engageable with the respective stoppers are provided at the gear holding lever.
Since the ink jet recording apparatus is thus constructed, the stopper-engaging portion is engaged with the stopper at one side when the gear holding lever is disposed at a rotation stop position at one side. On the other hand, the stopper-engaging portion is engaged with the stopper at the other side when the gear holding lever is disposed at the rotation stop position at the other side.
It is preferable that the fixing base is composed of a frame of an ink suction pump and an attaching base thereof.
Since the ink jet recording apparatus is thus constructed, one end portion of the drive shaft is rotatably and pivotally supported on the frame, and the other end portion is rotatably and pivotally supported at the attaching base.
Further, it is preferable that the gear holding lever is composed of a lever that is resiliently deformed by rotation of the cleaner drive lever in a state where the gear holding lever is locked at the rotation stop position.
Since the ink jet recording apparatus is thus constructed, when the cleaner drive lever turns, an impact resulting from engagement of the planet gear with the inner teeth can be absorbed by the gear holding gear.
The driving mechanism is caused to include a spring, by which the cleaner drive lever is positioned so as to be urged to the cleaner set position or the cleaner reset position, in line with release of the engagement between the planet gear and the inner teeth.
Since the ink jet recording apparatus is thus constructed, as the planet gear is disengaged from the inner teeth, the cleaner drive lever is positioned at the cleaner set position or the cleaner reset position by a repulsion force of the spring.
In this case, it is preferable that the spring is composed of a torsion spring, one end of which is fixed at the attaching base, and the other end of which is fixed at the cleaner drive lever.
Since the ink jet recording apparatus is thus constructed, when positioning the lever, the cleaner drive lever receives the repulsion force of the torsion spring at an end of the spring, and is urged to the cleaner set position or the cleaner reset position.
The ink jet recording apparatus is constructed so that the fixing positions of the spring in regard to the cleaner drive lever are the same fixing positions with respect to the cleaner set position and the cleaner reset position.
Therefore, the cleaner drive lever receives the repulsion force of the torsion spring from the same fixing position, and is urged to the cleaner set position or the cleaner reset position.
In this case, such a construction maybe employed, in which the fixing positions of the spring with respect to the cleaner drive lever are positions differing from each other at the cleaner set position and the cleaner reset position.
Since the ink jet recording apparatus is thus constructed, the cleaner drive lever receives the repulsion force of the torsion spring from positions differing from each other and is urged to the cleaner set position or the cleaner reset position.
It is preferable that the drive shaft is a pump drive shaft of the ink suction pump.
Since the ink jet recording apparatus is thus constructed, the rotation force of the pump drive shaft can be used as a driving force of the cleaner.
In this case, the above driving mechanism is constructed so that the driving mechanism applies a driving force to the cleaner so that the cleaner is caused to advance to the movement path by rotations of the pump drive shaft in the suction direction and is caused to retreat from the movement path by rotations in the direction opposed to the suction direction.
Since the ink jet recording apparatus is thus constructed, when the pump drive shaft rotates in the suction direction of ink, the cleaner advances from the outside of the movement path of the recording head to the inside of the movement path. On the other hand, when the pump drive shaft rotates in the direction opposed to the suction direction of ink, the cleaner is retreated from the inside of the movement path to the outside thereof.
Further, it is preferable that the driving force is an advancing and retreating force in the direction perpendicular to the reciprocation direction of the carriage.
Since the ink jet recording apparatus is thus constructed, the cleaner advances and retreats in the direction perpendicular to the movement path of the recording head by rotations of the pump drive shaft.